Karl Franzens University Graz

Graz University of Technology 

Quantum state control of a ground state H$_2$ molecule.
Prof. Dr. Gil Alexandrowicz
Swansea University
16:15 - 17:15 Tuesday 03 December 2024 TUG

Measurements of quantum-state-controlled collisions between gas phase molecules, and between molecules and surfaces, provide the ultimate test for theoretical modelling. Over the years many techniques have been developed to control the quantum states of the impinging molecules, which involve photo-excitation with lasers, steering of paramagnetic and polar molecules using strong field gradients, etc. One group of molecules these techniques cannot control are closed-shell ground-state molecules in general, and hydrogen molecules in particular. In the last decade our group has developed a technique for controlling the rotational projection quantum states of ground state hydrogen before a molecule-surface collision[1]. During the talk I will briefly explain the technique which is based on magnetic field manipulations of the molecules, show examples of how we can control and measure the outcome of elastic collisions[2], rotationally-inelastic collisions[3] and recently also chemical reactions (dissociation of H$_2$). I will also discuss how these experiments can contribute to the development of reliable theoretical modelling of surface systems.

[1] Nat. Commun. 8, 15357 (2017).
[2] Nat. Commun. 11, 3110 (2020).
[3] Nat. Commun. 13, 2287 (2022).